Soundproof material

Abstract

A soundproof material comprising a porous member having an air permeation amount based on the pressure difference of 2.039×1/10 4 mmH 2 O of from 1×1/10 10 to 2×1/10 2 cc/cm 2 /second, and having a compressibility.

What is claimed is: 
     
       1. A hard disc drive comprising: a hard disc drive body,   a substrate, and   a soundproof material comprising a compressible porous member which comprises a foam wherein: (1) an air permeation amount based on the pressure difference of 2.039×1/10 4  mmH 2  O is from 1×1/10 10  to 2×1/10 2  cc/cm 2  /second,   (2) at least 30% of cells of the foam have an open cell structure;   (3) the foam has a foaming ratio of 3 to 20 times; and   (4) the foam contains EPDM, interposed between the hard disc body and the substrate.     
     
     
       2. A hard disc drive as claimed in claim 1, wherein the soundproof material has an acoustic absorptivity at a frequency of 3.15 kHz of at least 20%. 
     
     
       3. A hard disc drive as claimed in claim 1, wherein the soundproof material has a repulsion stress at 50% compression of 10 to 200 gf/cm 2 .